The fabrication of a semiconductor device involves a plurality of discrete and complex processes. To perform these processes, a workpiece is typically disposed on a platen. The platen may be an electrostatic chuck, designed to retain the workpiece through the application of electrostatic forces produced by electrodes within the platen.
In some embodiments, one or more of these processes may be non-uniform, in that portions of the workpiece are processed more than other portions. For example, a deposition process may deposit more material on a first portion of a workpiece than a second portion. In another example, a chemical mechanical planarization (CMP) process may remove less material from the first portion than from the second portion. To compensate for this, it may be advantageous to subsequently process the workpiece unevenly. For example, it may be beneficial to subsequently etch more material from the first portion than from the second portion. This technique may result in a more uniform workpiece than can otherwise be achieved.
Further, some semiconductor processes are sensitive to temperature, such that their efficiency varies based on the temperature of the workpiece during processing. For example, an identical etching process may remove more material from a heated workpiece than from a cooler workpiece.
This phenomenon may be exploited to achieve better uniformity during workpiece processing. However, to perform this temperature sensitive processing, precise heating of small portions of the workpiece may be desired. However, techniques to selectively heat a workpiece may be imprecise or may not permit the desired resolution.
Therefore, it would be beneficial if there were a system and method for dynamically heating portions of the workpiece during workpiece processing that allowed the desired amount of temperature and spatial control.